Whether you want to save money on your utility bill or control the temperature of your home, these three tips will help you insulate your home and make it airtight. You will need to make the “envelope”
These are the most common air leakage problems in American homes that can make a big difference with little investment. Here’s how to do all three.
Airtight the ‘envelope’ of the house
First of all, you want to start by making the house airtight. This will give you the most improvement with the least investment. And it’s critical that you make the house airtight before putting in any insulation. Otherwise you will waste your time. Fibrous insulation needs an air barrier to work as it was intended to work, which is why it is recommended last.
When talking about air that seals the “envelope” of the home, it is important to note how air behaves naturally in a building. The pattern of air in and out of your home is known as the “stacking effect”. It essentially means that warm air rises and cold air dives. So warm air leaves your home through the attic and cold air enters through a crawl space, an unfinished basement, or some other unconditioned lower part of your home.
That’s why sealing the upper and lower floors of your home, along with insulation, is one of the best ways to prevent air leakage.
When a window is drafty it is immediately apparent to a homeowner, but leaks in attics or crawl spaces are usually worse, but usually hidden from view. And these areas will be the most beneficial to counteract the ‘stacking effect’.
You want to make window moldings, doors, vents, chimneys and flues for stoves and other things airtight, such as pipes and wires that pass through the “envelope” of the house.
Windows often have openings around the trim and under the sill. You can use a caulking gun to seal these. Cut the top of the pipe with caulk at a 45 degree angle. Use the pin under the gun to break the seal and insert the tube into the caulking gun. Insert the caulking gun and squeeze the trigger as you move along the frame. The 45 degree angle allows the tip to form the bead of the kit in a neat line while it is being applied, but it may still be necessary to touch up. You can do this easily with your finger. And don’t worry, the kit rinses off easily with water.
You can also use the caulking gun for areas such as an exhaust fan in the bathroom, floor vents, and other crevices. But as for a flue vent, you’ll want to make sure to use a fireproof sealant instead for areas that are more flammable to ensure fire safety. And before closing a flue with air, make sure the oven is off and there is no fire burning / you have allowed it to cool sufficiently.
You can now add a draft strip to make the frame of the front or rear door airtight. These doors may have a small gap between the door and the outside that not only allows light to pass through, but also allows air to enter. You can grab a weatherstrip kit that comes with everything you need.
First, you need to remove an old existing weatherstrip from your door frame. Then you can mount the new draft strip. It’s easier to start with the left and right sides of the frame first and then pressure fit the top. You will need to measure the side of your door frame and cut the weatherstrip to size. And when you cut it, make sure to cut it from the metal side – you’ll get a cleaner cut.
Close the door and make sure it is locked before installing the weatherstrip. If it is not locked and you install the weatherstrip too close, you could put a lot of stress on the lock and it could break or come out of the wood.
Align the weatherstripping tightly against the side of the door frame, but do not press too hard against the door. Use a power drill to place the first screw in the center, then the top and bottom. Now do the same steps for the other side – and again for the top.
Now, for tricky areas where a larger opening or wires are in the way, you can make these areas airtight with tin foam. It’s easier to just squirt the foam into these openings and let it expand.
To use the tin foam, attach the mouthpiece to the top and handle it gently. This will not come from your clothing or carpet.
Again, leaks in your attic or crawl space are the most important areas to address. For example, you can spray the tin foam on the openings around pipes and vents and the cracks in a crawl space and on the tops of the interior walls in the attic. If you have an unfinished basement instead of a crawl space, you can use caulk or foam to airtight seal the rim joist and sill plates.
Seal the pipework
On to the canal work. If your pipes are leaking and in an area without air conditioning (such as a crawl space, unfinished basement, basement, attic, and so on), literally heat or cool the outside air. So if you seal it, more of the heat / air conditioning that was meant for your home will come in.
Not only that, but sealing your ducts also improves the quality of your indoor air. If the duct is leaky, it can draw in dirt, dust, mold and possibly radon from the outside. By sealing the ductwork, the duct can only draw in air that is already in the house.
To seal the pipework in a lower area without air conditioning, you can use a sealant. Mastic is good for sealing pipe joints because it is liquid and can get into hard-to-reach places. It is also flexible as it resists expansion and contraction due to temperature changes.
This part is simple. With a rubber glove, you can literally dip your hand into the bucket of mastic and spread it along the seams, joints and holes of the metal ductwork. Be careful as metal ducts can have sharp edges.
Add attic insulation
And last but not least, you want to insulate your attic space. As mentioned earlier, insulating your attic before making the attic floor airtight has a minimal benefit.
When talking about insulating the attic space, it is important to note that the insulation and air barrier must be continuous and contiguous (meaning they touch each other). The continuous part is that it is more effective to have 6 inches of insulation everywhere rather than 10 inches of insulation in a concentrated spot. The adjacent part is where drywall is, insulation has to touch it. If it doesn’t touch (for example, if the insulation is on top of wires and not underneath), the insulation won’t do anything.
Another thing to note is that you want to make sure there is no air gap between the layers of batts, the insulation strips.
In other words, you want the insulation to be the same depth as the joists, if you are using mats and not loose (or blown) insulation, or else an air gap will be created when you use the second perpendicular layer of insulation.
If the depth is lower than the beam, there will be an air gap from the second layer; if the depth is higher than the beam, there is still an air gap between the beam and the second layer. Only the first layer should have the same depth, but the second perpendicular layer can be thicker.
And the first layer should be as thick as needed, depending on the Energy Star recommended R-value for your geographic location. The R value is a measure of how effective a material is to prevent heat loss. The higher the R value, the better.
Keep in mind that when insulating your attic, you want to make sure you wear protective gear and cover your skin to avoid inhaling or getting on your skin dust and fiberglass.
First, you need to clean the joist space so that the insulation can sit completely flat. Then place an insulation layer in the bay and cut the length to fit properly. Try to cut the mat as perfectly as possible, but it’s okay if you mess it up – as long as you fill the depth of the bay evenly with insulation.
Then add the second layer of mat perpendicular to the joists so that the wood is insulated as well and not just the bay.
Energy Audit and the Weatherization Assistance Program
These tips can help minimize air leakage and cold spots in your home. But if you want a more in-depth professional opinion before trying some of these methods, you can get adone at your home to see what specific areas your home is missing in terms of energy efficiency.
The United States Department of Energy also has a weather support program at the state and local levels if you qualify as low-income, over 60, or part of a family with disabilities. Consult your local utility company for more information.